Avenol was accused of using the League as an extension of the French Foreign Office in its policy of appeasement of Germany and Italy.

When World War II started on 1 September 1939, Avenol had decided to leave Geneva and the League of Nations for good on 31 August 1940.

His services were not accepted by the Vichy government, and he was forced to flee back into Switzerland on New Year's Eve 1943 to avoid getting arrested by the Germans.

When Seán Lester replaced him as secretary-general, the League had only 100 employees, including guards and janitors, out of its original 700.

Lester managed to keep the League's technical and humanitarian programs in limited operation for the duration of the war.